Enhanced visible-light photocatalytic activity of g-C<inf>3</inf>N<inf>4</inf>/TiO<inf>2</inf>films

Abstract

Enhanced photocatalytic degradation of methylene blue (MB) using graphitic carbon nitride/titanium dioxide (g-C3N4/TiO2) catalyst films has been demonstrated in this present work. The g-C3N4/TiO2composites were prepared by directly heating the mixture of melamine and pre-synthesized TiO2nanoparticles in Ar gas flow. The g-C3N4contents in the g-C3N4/TiO2composites were varied as 0, 20, 50 and 70wt%. It was found that the visible-light-induced photocatalytic degradation of MB was remarkably increased upon coupling TiO2with g-C3N4and the best degradation performance of ~70% was obtained from 50wt%g-C3N4loading content. Results from UV-vis absorption study, Electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy suggest that the improved photoactivity is due to a decrease in band gap energy, an increased light absorption in visible light region and possibly an enhanced electron-hole separation efficiency as a result of effective interfacial electron transfer between TiO2and g-C3N4of the g-C3N4/TiO2composite film. Based on the obtained results, the possible MB degradation mechanism is ascribed mainly to the generation of active species induced by the photogenerated electrons. © 2013 Elsevier Inc.